Magnetic resonance guided focused ultrasound thalamotomy for essential tremor

Magnetic resonance guided focused ultrasound thalamotomy for essential tremor

Magnetic resonance guided focused ultrasound is a minimally invasive surgical procedure for symptomatic treatment of Parkinson Disease. With this technology, the ventral intermediate nucleusSTN, and internal globus pallidus have been targeted for therapeutic cerebral ablation, while also minimizing the risk of hemorrhage and infection from more invasive neurosurgical procedures.

In a pilot study published in 2013, essential tremor improved in 15 patients treated with magnetic resonance guided focused ultrasound thalamotomy1).

Clinical trials have confirmed the efficacy of focused ultrasound (FUS) thalamotomy in essential tremor, but its effectiveness and safety for managing tremor-dominant Parkinson disease (TDPD) is unknown.

It might change the way that patients with essential tremor and potentially other disorders are treated 2).

Effectiveness

The post-treatment effectiveness was evaluated using the clinical rating scale for tremors. Thalamic MRgHIFU had substantial therapeutic effects on patients, based on MRgHIFU-mediated improvements in movement control and significant changes in brain mu rhythms. Ultrasonic thalamotomy may reduce hyper-excitable activity in the motor cortex, resulting in normalized behavioral activity after sonication treatment. Thus, non-invasive and spatially accurate MRgHIFU technology can serve as a potent therapeutic tool with broad clinical applications 3).

Safety

Magnetic resonance guided focused ultrasound (MRgFUS) for thalamotomy is a safe, effective and less-invasive surgical method for treating medication-refractory essential tremor (ET). However, several issues must be resolved before clinical application of MRgFUS, including optimal patient selection and management of patients during treatment 4).

Jung et al. found different MRI pattern evolution after MRgFUS for white matter and gray matter. Their results suggest that skull characteristics, such as low skull density, should be evaluated prior to MRgFUS to successfully achieve thermal rise 5).

Nursing management

In a large academic medical center in the mid-Atlantic region, the Department of Neurosurgery conducted a continued access study, recently approved by the Food and Drug Administration, to evaluate the effectiveness of transcranial FUS thalamotomy for the treatment of medication-refractory ET.

One patient’s experience will be introduced, including discussion of evidence-based treatment options for ET and information on the nursing management of the patient undergoing FUS thalamotomy 6).

Prospective randomized clinical trials

In a double-blinded, prospective, sham-controlled randomized controlled trial of MR-guided focused ultrasound thalamotomy for treatment of tremor-dominant PD, 62% of treated patients demonstrated improvement in tremor scores from baseline to 3 months postoperatively, as compared to 22% in the sham group. There has been only one open-label trial of MR-guided focused ultrasound subthalamotomy for patients with PD, demonstrating improvements of 71% for rigidity, 36% for akinesia, and 77% for tremor 6 months after treatment. Among the two open-label trials of MR-guided focused ultrasound pallidotomy for patients with PD, dyskinesia and overall motor scores improved up to 52% and 45% at 6 months postoperatively. Although MR-guided focused ultrasound thalamotomy is now approved by the U.S. Food and Drug Administration for treatment of parkinsonian tremor, additional high-quality randomized controlled trials are warranted and are underway to determine the safety and efficacy of MR-guided focused ultrasound subthalamotomy and pallidotomy for treatment of the cardinal features of PD. These studies will be paramount to aid clinicians to determine the ideal ablative target for individual patients. Additional work will be required to assess the durability of MR-guided focused ultrasound lesions, ideal timing of MR-guided focused ultrasound ablation in the course of PD, and the safety of performing bilateral lesions 7).

Case series

References

1)

Elias WJ, Huss D, Voss T, Loomba J, Khaled M, Zadicario E, Frysinger RC, Sperling SA, Wylie S, Monteith SJ, Druzgal J, Shah BB, Harrison M, Wintermark M. A pilot study of focused ultrasound thalamotomy for essential tremor. N Engl J Med. 2013 Aug 15;369(7):640-8. doi: 10.1056/NEJMoa1300962. PubMed PMID: 23944301.
2)

Lipsman N, Schwartz ML, Huang Y, Lee L, Sankar T, Chapman M, Hynynen K, Lozano AM. MR-guided focused ultrasound thalamotomy for essential tremor: a proof-of-concept study. Lancet Neurol. 2013 May;12(5):462-8. doi: 10.1016/S1474-4422(13)70048-6. Epub 2013 Mar 21. PubMed PMID: 23523144.
3)

Chang JW, Min BK, Kim BS, Chang WS, Lee YH. Neurophysiologic correlates of sonication treatment in patients with essential tremor. Ultrasound Med Biol. 2015 Jan;41(1):124-31. doi: 10.1016/j.ultrasmedbio.2014.08.008. Epub 2014 Oct 22. PubMed PMID: 25438838.
4)

Chang WS, Jung HH, Kweon EJ, Zadicario E, Rachmilevitch I, Chang JW. Unilateral magnetic resonance guided focused ultrasound thalamotomy for essential tremor: practices and clinicoradiological outcomes. J Neurol Neurosurg Psychiatry. 2015 Mar;86(3):257-64. doi: 10.1136/jnnp-2014-307642. Epub 2014 May 29. PubMed PMID: 24876191.
5)

Jung HH, Chang WS, Rachmilevitch I, Tlusty T, Zadicario E, Chang JW. Different magnetic resonance imaging patterns after transcranial magnetic resonance-guided focused ultrasound of the ventral intermediate nucleus of the thalamus and anterior limb of the internal capsule in patients with essential tremor or obsessive-compulsive disorder. J Neurosurg. 2015 Jan;122(1):162-8. doi: 10.3171/2014.8.JNS132603. PubMed PMID: 25343176.
6)

Shaw KD, Johnston AS, Rush-Evans S, Prather S, Maynard K. Nursing Management of the Patient Undergoing Focused Ultrasound: A New Treatment Option for Essential Tremor. J Neurosci Nurs. 2017 Aug 16. doi: 10.1097/JNN.0000000000000301. [Epub ahead of print] PubMed PMID: 28817495.
7)

Moosa S, Martínez-Fernández R, Elias WJ, Del Alamo M, Eisenberg HM, Fishman PS. The role of high-intensity focused ultrasound as a symptomatic treatment for Parkinson’s disease. Mov Disord. 2019 Jul 10. doi: 10.1002/mds.27779. [Epub ahead of print] Review. PubMed PMID: 31291491.

Magnetic resonance perfusion imaging in glioblastoma

Indications

Magnetic resonance perfusion imaging, may:

Provide a noninvasive diagnostic tool for properly grading lesions.

Identifying the most malignant region of a tumor for guiding biopsy

Monitoring response to therapy that may precede conventionally assessed changes in tumor morphology and enhancement characteristics.

May help quantitatively predict recurrent glioblastoma/progression for glioblastomas. The active tumor histological fraction correlated with quantitative radiologic measurements including rCBV and rCBF.

The dominant predictors of OS are normalized perfusion parameters Normalized Relative Tumor Blood Volume (n_rTBV) and Normalized Relative Tumor Blood Flow (n_rTBF). Pre-operative perfusion imaging may be used as a surrogate to predict glioblastoma aggressiveness and survival independent of treatment 1).


For metastases, Perfusion MRI may not be as useful in predicting mean active tumor fraction (AT). Clinicians must be judicious with their use of MRP in predicting tumor recurrence and radiation necrosis 2).

While perfusion MRI is not the ideal diagnostic method for differentiating glioma recurrence from pseudoprogression, it could improve diagnostic accuracy. Therefore, further research on combining perfusion MRI with other imaging modalities is warranted 3).

Perfusion-weighted magnetic resonance imaging (PW-MRI) techniques, such as dynamic contrast-enhanced MRI (DCE-MRI) and dynamic susceptibility contrast-MRI (DSC-MRI), have demonstrated much potential as powerful imaging biomarkers for glioma management as they can provide information of vascular hemodynamics 4) 5) 6).

PW-MRI is now rapidly expanding its application spectrum by noninvasively exploring the relationship between imaging parameters and the molecular characteristics of gliomas 7).


Dynamic contrast enhanced magnetic resonance imaging and Dynamic susceptibility weighted contrast enhanced perfusion imaging represent a widely accepted method to assess glioblastoma (GBM) microvasculature.

The aim of Navone et al. from the Laboratory of Experimental Neurosurgery and Cell Therapy, Neurosurgery Unit, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Postgraduate School in Radiodiagnostics Department of Neuroradiology, Milan, was to investigate the correlation between plasma von Willebrand Factor (VWF):Ag, permeability and perfusion MRI parameters, and examine their potential in predicting GBM patient prognosis.

They retrospectively analysed pre-operative DCE-, DSC-MRI, and VWF:Ag level of 26 GBM patients. They assessed the maximum values of relative cerebral blood flow (rCBF) and volume (rCBV), volume transfer constant Ktrans, plasma volume (Vp) and reflux rate constant between fractional volume of the extravascular space and blood plasma (Kep). Non-parametric Mann-Withney test and Kaplan-Meier survival analyses were conducted and a p-value<0.05 was considered statistically significant.

The median VWF:Ag value was 248 IU/dL and the median follow-up duration was about 13 months. They divided patients according to low- and high-VWF:Ag and found significant differences in the median follow-up duration (19 months vs 10 months, p=0.04) and in Ktrans (0.31 min-1 vs 0.53 min-1, p=0.02), and Kep (1.79 min-1 vs 3.89 min-1, p=0.005) values. The cumulative 1-year survival was significantly shorter in patients with high-VWF:Ag and high-Kep compared to patients with low-VWF:Ag and low-Kep (37.5% vs. 68%, p = 0.05).

These findings, in a small group of patients, suggest a role for VWF:Ag, similar to Ktrans, and Kep as a prognostic indicator of postoperative GBM patient survival 8).

References

1)

Hou BL, Wen S, Katsevman GA, Liu H, Urhie O, Turner RC, Carpenter J, Bhatia S. MRI Parameters and Their Impact on the Survival of Patients with Glioblastoma: Tumor Perfusion Predicts Survival. World Neurosurg. 2018 Dec 26. pii: S1878-8750(18)32908-5. doi: 10.1016/j.wneu.2018.12.085. [Epub ahead of print] PubMed PMID: 30593971.
2)

Shah AH, Kuchakulla M, Ibrahim GM, Dadheech E, Komotar RJ, Gultekin SH, Ivan ME. The utility of Magnetic Resonance Perfusion imaging in quantifying active tumor fraction and radiation necrosis in recurrent intracranial tumors. World Neurosurg. 2018 Oct 9. pii: S1878-8750(18)32288-5. doi: 10.1016/j.wneu.2018.09.233. [Epub ahead of print] PubMed PMID: 30312826.
3)

Wan B, Wang S, Tu M, Wu B, Han P, Xu H. The diagnostic performance of perfusion MRI for differentiating glioma recurrence from pseudoprogression: A meta-analysis. Medicine (Baltimore). 2017 Mar;96(11):e6333. doi: 10.1097/MD.0000000000006333. PubMed PMID: 28296759; PubMed Central PMCID: PMC5369914.
4)

Jain R. Measurements of tumor vascular leakiness using DCE in brain tumors: clinical applications. NMR in Biomedicine. 2013;26(8):1042–1049. doi: 10.1002/nbm.2994.
5)

O’Connor J. P. B., Jackson A., Parker G. J. M., Roberts C., Jayson G. C. Dynamic contrast-enhanced MRI in clinical trials of antivascular therapies. Nature Reviews Clinical Oncology. 2012;9(3):167–177. doi: 10.1038/nrclinonc.2012.2.
6)

Barajas R. F. R., Cha S. Benefits of dynamic susceptibility-weighted contrast-enhanced perfusion MRI for glioma diagnosis and therapy. CNS oncology. 2014;3(6):407–419. doi: 10.2217/cns.14.44.
7)

Chung C., Metser U., Ménard C. Advances in magnetic resonance imaging and positron emission tomography imaging for grading and molecular characterization of glioma. Seminars in Radiation Oncology. 2015;25(3):164–171. doi: 10.1016/j.semradonc.2015.02.002.
8)

Navone SE, Doniselli FM, Summers P, Guarnaccia L, Rampini P, Locatelli M, Campanella R, Marfia G, Costa A. Correlation of preoperative Von Willebrand Factor with MRI perfusion and permeability parameters as predictors of prognosis in glioblastoma. World Neurosurg. 2018 Oct 9. pii: S1878-8750(18)32271-X. doi: 10.1016/j.wneu.2018.09.216. [Epub ahead of print] PubMed PMID: 30312827.

Repetitive transcranial magnetic stimulation for stroke

Repetitive transcranial magnetic stimulation (rTMS) combined with treadmill training has been suggested to modulate corticomotor activity and improve gait performance in people with Parkinson’s disease.

It is unclear whether this combination therapy has a similar effect in people with stroke.

Review

Studies included in a review were identified by searching PubMed and ISI Web of Science. The search terms were (rTMS OR “repetitive transcranial magnetic stimulation”) AND (stroke OR “cerebrovascular accident” OR CVA) AND (rehab OR rehabilitation OR recover*). The retrieved records were assessed for eligibility and the most relevant features extracted to a summary table.

Seventy out of 691 records were deemed eligible, according to the selection criteria. The majority of the articles report rTMS showing potential in improving motor function, although some negative reports, all from randomized controlled trials, contradict this claim. Future studies are needed because there is a possibility that a bias for non-publication of negative results may be present.

rTMS has been shown to be a promising tool for stroke rehabilitation, in spite of the lack of standard operational procedures and harmonization. Efforts should be devoted to provide a greater understanding of the underlying mechanisms and protocol standardization 1).

Case series

A study of Wang et al., from the Taipei Veterans General Hospital aimed to investigate whether high-frequency rTMS enhances the effects of subsequent treadmill training in individuals with chronic stroke.

Fourteen participants meeting the selection criteria were randomly assigned to either the experimental (n = 8) or control (n = 6) group. The experimental group received 5 Hz rTMS prior to treadmill training three times per week for 3 weeks. The control group received sham rTMS before treadmill training. Walking speed, gait symmetry, corticomotor excitability, motor function of the lower extremities, and muscle activity during walking were measured before intervention, after intervention, and at 1-month follow-up.

The walking speed, spatial asymmetry of gait, and motor function of the lower extremities improved significantly in the experimental group, and these improvements exhibited significant differences in between-group comparisons. However, there was no significant difference in corticomotor excitability or brain asymmetry ratio after the intervention in each group.

The current results revealed that applying 5 Hz high-frequency rTMS over the leg motor cortex in the affected hemisphere enhanced the effects of subsequent treadmill training on gait speed and spatial asymmetry in individuals with chronic stroke. Improvement in gait speed persisted for at least 1 month in individuals with chronic stroke 2).


Bates and Rodger, used it in motor functional recovery from cerebral ischemic stroke to illustrate the difficulties in interpreting and assessing the therapeutic potential of rTMS for neurotrauma in terms of the presumed mechanisms of action of rTMS 3).

References

1)

Dionísio A, Duarte IC, Patrício M, Castelo-Branco M. The Use of Repetitive Transcranial Magnetic Stimulation for Stroke Rehabilitation: A Systematic Review. J Stroke Cerebrovasc Dis. 2018 Jan;27(1):1-31. doi: 10.1016/j.jstrokecerebrovasdis.2017.09.008. Epub 2017 Oct 27. Review. PubMed PMID: 29111342.
2)

Wang RY, Wang FY, Huang SF, Yang YR. High-frequency repetitive transcranial magnetic stimulation enhanced treadmill training effects on gait performance in individuals with chronic stroke: A double-blinded randomized controlled pilot trial. Gait Posture. 2018 Dec 18;68:382-387. doi: 10.1016/j.gaitpost.2018.12.023. [Epub ahead of print] PubMed PMID: 30586670.
3)

Bates KA, Rodger J. Repetitive transcranial magnetic stimulation for stroke rehabilitation-potential therapy or misplaced hope? Restor Neurol Neurosci. 2015;33(4):557-69. doi: 10.3233/RNN-130359. Review. PubMed PMID: 24595227
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